Results are reported from a three-dimensional computational stability analysis of flow over a backward-facing step with an expansion ratio (outlet to inlet height) of 2 at Reynolds numbers between 450 and 1050. The analysis shows that the first absolute linear instability of the steady two-dimensional flow is a steady three-dimensional bifurcation at a critical Reynolds number of 748. The criti...

A 2D Navier-Stokes solver was developed to simulate steady,laminar flow over a backward-facing step of height h. The step expansion ratio=1/2 and the flow at the step was assumed to be fully developed, laminar channel flow. The Reynolds number for this flow was defined as Re=Uh/ν. The 2D incompressible Navier-Stokes equations was solved in generalized curvilinear coordinates using artificial co...

Laser-Doppler velocity measurements adjacent to the bounding walls of three-dimensional (3-D) backward-facing step flow are performed for the purpose of mapping the boundaries of the reverse flow regions that develop in this geometry (adjacent to the sidewalls, the flat wall and the stepped wall) as a function of the Reynolds number. The backward-facing step geometry is configured by a step hei...

The water surface response to subcritical turbulent flow over a backward-facing step (BFS) is studied via high-resolution large-eddy simulation (LES). LES method validated first using data of previously reported experiments. LES-predicted decomposed into different types gravity waves as well turbulence-driven forced waves. Analysis the reveals interplay between low-frequency large-scale turbule...

Simulations of three-dimensional laminar forced convection adjacent to inclined backward-facing step in rectangular duct are presented to examine effects of step inclination on flow and heat transfer distributions. The step height is maintained as constant while its inclination angle is changed from 15 to 90 . The inlet flow is hydrodynamically steady and fully developed with uniform temperatur...

In this note suboptimal distributed and boundary control strategies for uid ows governed by the Navier-Stokes equation (NSE) together with aspects of the numerical and practical implementation of the underlying algorithms are presented. The objective of our numerical investigations is the development of practically relevant feedback control laws for ows over the backward facing step. For what f...